Vermiculite: Characteristics
The accordion mineral, and what buyers check
What this tab covers The supply and physical characteristics of the commodity. Supply: current production, inventories and stocks, capacity utilisation, geographic and producer concentration, how fast supply responds to price, the project pipeline and capital spending, and logistics and export flows. Material: the physical and chemical properties that set its grade, price and end uses (for example purity and conductivity for metals, API gravity, sulfur and energy content for fuels, moisture, protein and fibre quality for crops).Supply volume characteristics
| Characteristic | Figure | What it means | Source |
|---|---|---|---|
| Current production volume | about 460,000 t of concentrate (2025e, USGS); 524,000 t (2024, World Mining Data) | South Africa produced about 160,000 t (35%), the US 100,000 t (22%) and Brazil 50,000 t (11%). Sources differ because some countries report crude ore and others concentrate. | USGS MCS 2026, Vermiculite; World Mining Data 2026 |
| Inventory and stock levels | not published | No exchange or government stocks exist (US Government Stockpile: none). Exfoliators hold concentrate in sheds, and the US imported about 38,000 t in 2025 to supplement domestic mines. | USGS MCS 2026 |
| Capacity utilisation | not published | Palabora's output was 155,000 t in 2019 and South Africa's about 160,000 t in 2025, suggesting the main mine runs near a steady rate. The 12 US exfoliating plants processed about 55,000 t in 2025; their capacity is not reported. | MiningDataOnline 2019; USGS MCS 2026 |
| Geographic and producer concentration | South Africa 35%; top-3 (South Africa, US, Brazil) about 67%; HHI about 2,000 (USGS 2025) or 1,754 (World Mining Data 2024) | One company, Palabora Mining Company, supplies roughly a third of the world. The US output comes from two companies in South Carolina and Virginia. Only about a dozen countries mine it. | USGS MCS 2026 (HHI computed from country table); World Mining Data 2026 |
| Supply elasticity | low: few deposits are clean enough and new mines are rare | Ore must be free of amphibole asbestos since the Libby, Montana mine closed in 1990, which narrows usable deposits. Reserves are large relative to output (US 25 Mt, South Africa 14 Mt, Turkey 11 Mt), so the constraint is quality and permits, not geology. Buyers respond to tight supply by switching to perlite. | USGS MCS 2026 |
| Project pipeline and CapEx | not published | No new large projects are reported. Zimbabwe (30,000 t) and Uganda (20,000 t) are the smaller growing suppliers; Turkey and India hold reserves (11 Mt and 1.6 Mt) far above their output. | USGS MCS 2026 |
| Logistics and export flows | dense concentrate is traded; light exfoliated product is made near customers | The US imported 38,000 t in 2025, and Brazil and South Africa supplied 89% of US imports in 2021-24. India imported 80,000 t of HS 253010 material (which also covers perlite and chlorite) in 2024. South African exports averaged about $298/t (2024, Comtrade, indicative). Shipping exfoliated vermiculite would mean moving ten times the volume. | USGS MCS 2026; UN Comtrade 2024 |
Material characteristics Industrial mineral
Vermiculite is a hydrated mica that swells like an accordion when flash-heated, as water between its layers turns to steam. Value depends on flake size, how much it expands, its bulk density after expansion and freedom from asbestos. Exfoliated grades are light, fire-resistant and hold water and nutrients, which suits potting mixes, insulation and fire-protective plasters.
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Flake size grade | Palabora sells grades from 8-2.8 mm (premium) down to 0.71-0.25 mm (micron) | Coarser grades expand more and command higher prices; fine grades go to plasters and boards | Palabora Mining Company product data |
| Bulk density, crude concentrate | about 700-1,050 kg/m3 | Determines freight cost per tonne and is used to check grade | Palabora Mining Company product data |
| Bulk density, exfoliated | about 64-160 kg/m3 for loose-fill insulation (indicative) | Low density gives insulation value and light weight in concrete and plaster | ASTM C516 (indicative) |
| Expansion ratio | volume increases roughly 8-30 times on exfoliation (indicative) | Sets how much saleable product a tonne of concentrate yields | industry data, indicative |
| Asbestos content | must test free of amphibole fibres | Libby, Montana ore contaminated with amphibole asbestos caused disease and closed the mine in 1990; buyers demand certified clean ore | USGS MCS 2026 |
| Cation exchange capacity | high, roughly 100-150 meq/100 g (indicative) | Lets horticultural grades hold potassium, ammonium and magnesium for plants | soil science literature, indicative |